A motor vehicle may employ a wet clutch mechanism and/or a wet brake mechanism to help govern operation of the vehicle. Several components within a vehicle powertrain, for instance, may employ a wet clutch mechanism to facilitate the transfer of power from the vehicle's power generator (i.e, an internal combustion engine, electric motor, fuel cell, etc.) to the drive wheels. A transmission located downstream from the power generator which enables vehicle launch, gear shifting, and other torque transfer events is one such component. Some form of a wet clutch mechanism may be found throughout many different types of transmissions currently available for motor vehicle operation. A multi-plate wet clutch pack for an automatic transmission, a continuously variable transmission (CVT), or a dual-clutch transmission (DCT) is one particular example. Other types of wet clutch mechanisms may also be found in the transmission or elsewhere in the vehicle powertrain such as, for example, in a transfer case or an all-wheel drive unit. A wet brake mechanism functions and operates similar to a wet clutch mechanism but is used within the vehicle braking system to slow, stop, or otherwise restrict rotation of the drive wheels.
A typical multi-plate wet clutch pack (for a wet clutch or a wet brake mechanism) includes a set of friction plates and a set of reaction plates in which the two sets of plates are interleaved in coaxial facing alignment. The friction plates are typically comprised of an annular core plate and a friction facing bonded to one, and usually both, of the opposed annular working surfaces of the core plate. The friction facing may include a plurality of friction material segments situated around the core plate so that radially-extending channels are defined between pairs of adjacent segments. The reaction plates are constructed similarly to the friction plates but without the friction facing. Each set of plates is splined at an inner or outer circumferential edge to independent yet proximally situated support members. The friction plates and the reaction plates can be routinely engaged—or squeezed together—in the presence of a lubricant fluid to selectively to effectuate a torque transfer event or a braking event. Such recurring engagement and disengagement of the friction plates with their neighboring reaction plates is facilitated by the annularly-disposed friction facing present on the friction plates.
The manufacture of a friction plate generally involves deriving the individual friction material segments from a friction material source, such as a roll of friction material sheet stock, and then bonding them to one or both surfaces of the core plate to form the friction facing. A wide variety of approaches that present differing levels of manufacturing complexity and cost structure and, in some instances, friction facing performance, have been devised for making a friction plate. Nevertheless, the development of methods and apparatuses that can easily, reliably, and flexibly make friction plates with well-performing friction facings is constantly being pursued.